The present invention relates to mechanism including a ball bearing assembly for members adapted for longitudinal movement relative to one another.
These assemblies typically comprise a shaft mounted in the bore of a housing and a ball bearing assembly surrounding the shaft and of a configuration and orientation to effect longitudinal or axial displacement of the shaft relative to the housing upon rotation of the shaft. These assemblies usually include a cage with ball guides arranged to effect movement of the balls in an endless path.
In a prior known ball bearing of the type described, the curvature of the deflector tracks of each ball guide passes through the centers of the balls and its radius is considerably larger than half the diameter of the balls thereby forming radially projecting island sections on the cage which guide the balls of two adjacent guide tracks of an individual ball guide at a relatively large distance from each other in the longitudinal direction. This arrangement is shown in West German registered design No. 73-45379. By reason of this large distance, each ball guide requires a relatively large amount of space in the peripheral direction for installation. By reason of this, it is possible to house only a relatively small number of ball guides. This, in turn, results in a reduction in load capacity of the ball bearing which depending on the application in some instances is not sufficient.
The above problem may be solved in principle by shifting the guide track of the unloaded balls of each ball guide radially outwardly with respect to the associated or complementary guide track of the loaded balls so that the two guide tracks are arranged to some extent radially one on top of the other. This arrangement, however, would consume a relatively large amount of space in the radial direction which is undesirable in many cases.